Petroleum reservoir engineering support for the Office of Naval Petroleum and Oil Shale Reserves. 26R reservoir, recommended MER (addendum). Final technical report

Technical Report · Wed Oct 01 04:00:00 EDT 1986

OSTI ID:5159638

During the course of the study which was made for the preparation of the 26R Maximum Efficient Rates (MER) report, several concepts evolved which raised some concern as to whether the current program is the optimum for achieving maximum ultimate recovery and economic return as required by the ''Procedures.'' These concerns, and a discussion thereof, are the subject of this addendum to the MER report. (1) In order for gravity drainage to be most effective, The flow potentials in the reservoir must be downward for oil and upward for gas. On the basis of recent pressure surveys taken in Section 26R wells, it appears that this balance may have broken down, and that one reason for the high gas-oil ratios in down-structure wells is that the flow potential for gas is also downward. High gas injection rates are seen as a possible culprit in this regard. (2) It is a well-established feature of the Buckley-Leverett principle of fractional flow that in a gravity drainage mechanism, the residual oil saturation is inversely proportional to the total flow rate, i.e., oil plus gas. It follows that too high a rate of gas injection can be detrimental to oil recovery, and we are concerned that this may be the case in the 26R reservoir. (3) The cost of gas injection at anticipated levels will have a serious impact on the profitability of the 26R reservoir. The cost of the gas alone (and not including the cost of injection) will be some $800,000,000 over the next five years. (4) The effort to maintain pressure by gas injection alone may require such high levels of injection as to be counter-productive to the objective of maximizing oil recovery. It will almost certainly have a serious impact on the economic recovery. (5) It is not being recommended that gas injection be terminated - rather that it be reduced to the rate at which gravity segregation is reestablished as determined by field performance.

• Research Organization: Evans, Carey and Crozier, Bakersfield, CA (USA)
• DOE Contract Number: AC01-85FE60600
• OSTI ID: 5159638
• Report Number(s): DOE/FE/60600-T3; ON: DE87001325
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
020700 -- Petroleum-- Economics
Industrial
& Business Aspects
DATA
DRAINAGE
ECONOMIC ANALYSIS
ECONOMICS
ENERGY SOURCES
ENHANCED RECOVERY
EXPERIMENTAL DATA
FLUID INJECTION
FOSSIL FUELS
FUELS
GAS INJECTION
GAS SATURATION
GEOLOGIC DEPOSITS
INFORMATION
MINERAL RESOURCES
NAVAL PETROLEUM RESERVE
NUMERICAL DATA
OIL WELLS
PETROLEUM
PETROLEUM DEPOSITS
PRODUCTION
RECOMMENDATIONS
RECOVERY
RESERVES
RESOURCES
SATURATION
WELLS